Operations research in the management of the airlines

This paper is intended to present an introduction to the use of operations research in the international airline industry, and to demonstrate the scope and significance of the airline OR activities. First, the special reasons for the viability and spread of airline OR are discussed. Then a functional framework for an airline is outlined, to be used in analyzing the problems of an airline and relating the OR work to it. Four major applications are described, corresponding to four major components of the framework. These applications are: schedule development, overbooking control, crew scheduling and engine management, respectively. In each case we describe the problem and its significance, indicate the types of solution techniques which have been developed, and assess the implemented solutions. The paper concludes with comments on the current state-of-the-art and the future of airline OR. A detailed bibliography is given.Both of the authors have been operations research directors in major airlines and more recently have focused their attention upon the industry as academic researchers. This background has provided us with an unusual opportunity to analyze the role of OR in the airlines, and our paper seeks to share with the reader some of the insights we have gained thereby.     

股东参与治理的私人收益和社会收益的实证研究

本文探讨了股东参与治理所带来的私人收益、特定股权结构的社会收益以及股权集中成本三者之间的关系。我们分析的结果表明,当股东与经理人员之间的利益冲突水平较高、其它治理机制的作用较弱时,股权集中(股东参与治理的积极性较高)可以创造大量的社会收益;反之,股权的集中与分散程度(股东参与治理的积极性较低)对社会收益的影响不明显。本文的研究结论为我国股东参与治理及股权结构改革提供了重要启示。     

Early Adult Obesity and U.S. Women's Lifetime Childbearing Experiences

Literature from multiple disciplines suggests that women who are obese during early adulthood may accumulate social and physiological impediments to childbearing across their reproductive lives. This led the authors to investigate whether obese young women have different lifetime childbearing experiences than leaner peers by analyzing data from 1,658 female participants in the 1979 National Longitudinal Survey of Youth. Study sample members were nulliparous women ages 20–25 in 1982. The authors examined their childbearing experiences between 1982 and 2006 and found that young women who were obese at baseline had higher odds of remaining childless and increased odds of underachieving fertility intentions than young women who were normal weight at baseline. These results suggest that obesity has long‐term ramifications for women's childbearing experiences with respect to whether and how many children women have in general and relative to the number of children they want.     

The Protective Effect of Marriage for Survival: A Review and Update

The theory that marriage has protective effects for survival has itself lived for more than 100 years since Durkheim’s groundbreaking study of suicide (Durkheim 1951 [1897]). Investigations of differences in this protective effect by gender, by age, and in contrast to different unmarried statuses, however, have yielded inconsistent conclusions. These investigations typically either use data in which marital status and other covariates are observed in cross-sectional surveys up to 10 years before mortality exposure, or use data from panel surveys with much smaller sample sizes. Their conclusions are usually not based on formal statistical tests of contrasts between men and women or between never-married, divorced/separated, and widowed statuses. Using large-scale pooled panel survey data linked to death registrations and earnings histories for U.S. men and women aged 25 and older, and with appropriate contrast tests, we find a consistent survival advantage for married over unmarried men and women, and an additional survival “premium” for married men. We find little evidence of mortality differences between never-married, divorced/separated, and widowed statuses.     

Racial and Ethnic Differences in the Timing of First Marriage and Smoking Cessation

Using data from the National Longitudinal Survey of Youth 1979 (N = 4,050), we consider the relationship between the timing of family formation and positive changes in health behavior. Theories that predict both positive and negative associations are tested. The findings suggest that both mechanisms operate and that the direction of the association depends on the respondent’s race or ethnicity. Whites who marry early are less likely to quit smoking, whereas Whites who marry on time and Blacks and Hispanics who marry at all ages are more likely to quit. The analysis refines the understanding of how family formation shapes changes in health behaviors differentially across the life course, and it underscores the difference in this process for individuals from different racial and ethnic backgrounds.